What is broken? Expected lifetime, perception of brokenness and attitude towards maintenance and repair

This paper addresses the discrepancy between the expected and actual lifetimes of vacuum cleaners considering perceived ‘brokenness’ as a driver for replacement. Among electrical products, vacuum cleaners have a high rate of domestic ownership in the UK. They also embody large quantities of greenhouse gases which could be reduced by increasing their longevity and resource efficiency (Schreiber et al., 2012). A focus on energy efficiency has only shown limited or even negative results, therefore to meet recent European Union regulations on durability requirements a focus on product longevity is needed. Around one half of new vacuum cleaner purchasers replace one less than 5 years old, below the expected lifespan, with perceived breakage, poor performance and unreliability as the major reasons for replacement. Their relative simplicity could allow vacuum cleaners to last for significantly longer. The nature of the common causes of failure is known, including stretched cords or blockages, and WRAP has developed guidelines for product improvements. However, many working or repairable machines are disposed of because they are perceived to be ‘irremediably’ broken

The joy of vacuuming? How the user experience affects vacuum cleaner longevity

An apparent reduction in the average lifetime of vacuum cleaners is explored in this paper in relation to their perceived usability and increasingly frequent product replacement. Motivations for product disposal combine perceived and real product failure with a perceived or real improved product offer. From an historical perspective, vacuum cleaners typify this pattern, continually offering a ‘cheaper and improved’ product. Vacuum cleaner manufacturers reinvigorate the sense of satisfaction and revulsion associated with extracting dirt from our homes through new performance focused product development. For example, increased motor power, filtration, bag-less machines and clear bin compartments have all acted as sales drivers, whilst cost effective materials and offshore and more efficient manufacturing have reduced purchase prices. The latter, cost-driven, processes can create machines that are more likely to be functionally and aesthetically damaged in use, reinforcing the trend for faster replacement. The market appears likely to continue to focus on improved user experience, with growth in market share for lighter weight cordless battery powered machines posing the risk of an increased environmental burden. Drawing from qualitative and quantitative research undertaken for a study for Defra, we explore the user’s relationship to the product, investigating the frustrations and joys of vacuum cleaner use and ownership. The findings illustrate that the revulsion and attraction of cleaning, as well as the tedium and satisfaction fostered by the product, have direct implications for vacuum cleaner longevity

The relationship between ideas about cleanliness and actions that affect product longevity

As Mary Douglas famously put it, ‘where there is dirt there is system’ (1991 (1966): 35). She was concerned particularly with the cultural systems that determine the ideas about dirt that motivate and constrain people’s actions with material objects. This paper assumes that such motivations and constraints may affect consumers’ willingness to keep or to dispose of their possessions, and therefore have an impact on product longevity. It reports on ongoing empirical research using product analysis, ethnographic interviews, a questionnaire and student design work into the possibility of increasing the longevity of vacuum cleaners by design interventions. Because its object of study is a cleaning product used in everyday cleaning practices, the research naturally connects with Douglas’ ideas as well as more recent work such as Dant 2003 that focuses on how people deal practically with the materiality of dirt, not determined by cultural categories. This paper builds on Vaussard et al.’s (2014) classification of individuals by their degree of concern for keeping their house clean, into ‘Spartan’, ‘Minimalistic’, ‘Caring’ and ‘Committed’ cleaners and their implications for vacuum cleaner replacement. Introducing a short history of concern about dirt since germ theory, it considers whether the desire for a more up to date/efficient/powerful/good looking/clean/shiny machine may accelerate replacement. It finally considers whether a design that ‘ages gracefully’ might have a longer life-span, either as a personal possession or as part of a service system

Human engineering design criteria study Final report

Human engineering design criteria for use in designing earth launch vehicle systems and equipmen

A Preliminary Discussion of the Kinematics of BHB and RR Lyrae Stars near the North Galactic Pole

The radial velocity dispersion of 67 RR Lyrae variable and blue horizontal branch (BHB) stars that are more than 4 kpc above the galactic plane at the North Galactic Pole is 110 km/sec and shows no trend with Z (the height above the galactic plane). Nine stars with Z < 4 kpc show a smaller velocity dispersion (40 +/-9 km/sec) as is to be expected if they mostly belong to a population with a flatter distribution. Both RR Lyrae stars and BHB stars show evidence of stream motion; the most significant is in fields RR2 and RR3 where 24 stars in the range 4.0 < Z < 11.0 kpc have a mean radial velocity of -59 +/- 16 km/sec. Three halo stars in field RR 2 appear to be part of a moving group with a common radial velocity of -90 km/sec. The streaming phenomenon therefore occurs over a range of spatial scales. The BHB and RR Lyrae stars in our sample both have a similar range of metallicity (-1.2 < [Fe/H] < -2.2). Proper motions of BHB stars in fields SA 57 (NGP) and the Anticenter field (RR 7) (both of which lie close to the meridional plane of the Galaxy) show that the stars that have Z 4 kpc have a Galactic V motion that is < -200 km/sec and which is characteristic of the halo. Thus the stars that have a flatter distribution are really halo stars and not members of the metal-weak thick-disk.Comment: Accepted for publication in the March 1996 AJ. 15 pages, AASTeX V4.0 latex format (including figures), 2 eps figures, 2 separate AASTeX V4.0 latex table

Dirt, damage, servicing and repair: understanding motivations for product disposal. Technical report

Sustainable consumption requires increased product longevity, not least because the fast throughput of consumer goods adds to the threat of climate change due to embodied greenhouse gas emissions. Vacuum cleaners are the second largest source of embodied emissions among electrical products in the UK, and today’s consumers only expect them to last around 5 years, perhaps a third of typical life-spans in the past. This report presents the findings of a research project funded by Defra in order to find solutions to inadequate vacuum cleaner lifetimes. The project involved a multi-method research process that led to the development of a practical toolkit with potential solutions. The first phase of the research comprised a scoping exercise with a literature review, stakeholder interviews, over 100 user interviews and a product teardown exercise. Through this, five themes were identified as the basis for design interventions to increase vacuum cleaner longevity: Ageing Gracefully, Optimal Construction, Information Provision, Enjoyable Experience, Servicing Systems. The themes were explored in the second phase through a survey of over 500 consumers, a user co-creation workshop with 30 participants, and a workshop involving the research team and five employees of a leading vacuum cleaner manufacturer. During this phase five final year Product Design undergraduates were recruited to develop product concepts based on the themes. The results of the survey support the view that many vacuum cleaners are discarded after a short period. It suggested that key challenges were: creating the perception of the vacuum cleaner as a pleasant object and vacuuming as an enjoyable task; motivating constant and effective maintenance; communicating information to users effectively, and encouraging periodic servicing and repair. The co-creation workshop revealed key elements of vacuum cleaning from a user perspective, including frustrations such as a heavy, noisy or smelly vacuum cleaner, perhaps with an unsatisfactory cord or hose. Through this work product concepts for ‘ideal’ vacuum cleaners were developed for each of the themes: Ageing Gracefully: A robust, attractive, high performance product that ages well, offering high performance and retaining an ‘as new’ sensorial quality (e.g. visual, noise, smell). Optimal Construction: A long lasting motor body with a convenient recyclable head unit containing typically serviceable elements, e.g. dirt container, filters and brushes. Information Provision: A product designed to communicate performance levels and assist faultfinding, enhancing user interaction from when first unpacked and assembled, and with wireless internet communication of product status to the manufacturer. Enjoyable Experience: Enhanced emotional attachment through consideration of material choice, ease of use and storage, and reduced contact with dirt. Servicing Systems: A leasing system providing users with a high quality machine (either new or remanufactured) at a lower long-term cost, with benefits such as free servicing. The manufacturer workshop revealed that lightweight, easy to use and cordless products are of growing importance in the industry sector. The Information Provision and Optimal Construction product concepts were especially well received and considered most promising. In the third and final phase, the concepts were refined through a focus group involving 15 users, which provided feedback on prototype products. A toolkit for product development teams was created in the form of cards that display 28 components (i.e. product features) generated through a product concept development process. Each card has information on the type of cleaner most likely to be attracted to a particular product feature and the actor (i.e. industry, policy makers, consumers) most able to influence its implementation. The product concepts and features were then tested through a second survey, again using a consumer panel, which attracted over 550 respondents. This investigated how the concepts and features might influence purchase decisions and whether consumers felt they would influence the vacuum cleaner’s longevity. Lastly, the toolkit was tested with five industry stakeholders (four manufacturers and a repairer) to consider commercial feasibility

Design, dirt and disposal: influences on the maintenance of vacuum cleaners

This paper explores the relationship between people's feelings about dirt, and an apparent reduction in the lifetime of vacuum cleaners. The short life-spans of vacuum cleaners is a significant environmental issue. In addition to the waste generated, they have an impact on climate change: vacuum cleaners account for the second largest embodied greenhouse gas emissions of electrical goods in the UK after televisions, largely because of their high sales volumes. Drawing from qualitative and quantitative research undertaken for the UK Department for Environment, Food & Rural Affairs (Defra), the paper demonstrates that one motivation for vacuum cleaner replacement is the increased enjoyment from dirt removal that a new vacuum cleaner may provide. The paper also shows that premature disposal can occur once a product becomes dirty and visually damaged, and whilst functional, is perceived to be less effective. Solutions to premature disposal were explored through the co-creation of design concepts and design features were tested via an online survey. Vacuum cleaner users were clustered into four cleaner types; Spartan, Minimal, Caring and Manic. Overall, respondents reported that improving the ease of maintaining vacuum cleaners would be the most effective way to help them to increase their vacuum cleaner's longevity. Across all cleaner types maintenance levels were low, although Caring and Manic cleaners were significantly more likely to undertake such tasks. Motivations for disposal were similar across cleaner types and we found no evidence that Caring and Manic cleaners disposed of their machines earlier because they were 'worn out.' We discovered that Caring and Manic cleaners spend the most on their vacuum cleaners, vacuum more often and are the most likely to replace their machine after the shortest period. Those willing to do 'a lot more' to help the environment were significantly more likely to want to 'keep the floors in my home spotlessly clean' and significantly more likely to indicate that they preferred their vacuum cleaner to look new. Consequently, the paper proposes that design interventions to increase vacuum longevity should be targeted toward Caring and Manic cleaners and concludes with key design recommendations for these two cleaner types

A general approximation of quantum graph vertex couplings by scaled Schroedinger operators on thin branched manifolds

We demonstrate that any self-adjoint coupling in a quantum graph vertex can be approximated by a family of magnetic Schroedinger operators on a tubular network built over the graph. If such a manifold has a boundary, Neumann conditions are imposed at it. The procedure involves a local change of graph topology in the vicinity of the vertex; the approximation scheme constructed on the graph is subsequently `lifted' to the manifold. For the corresponding operator a norm-resolvent convergence is proved, with the natural identification map, as the tube diameters tend to zero.Comment: 19 pages, one figure; introduction amended and some references added, to appear in CM

Strategies used as spectroscopy of financial markets reveal new stylized facts

We propose a new set of stylized facts quantifying the structure of financial markets. The key idea is to study the combined structure of both investment strategies and prices in order to open a qualitatively new level of understanding of financial and economic markets. We study the detailed order flow on the Shenzhen Stock Exchange of China for the whole year of 2003. This enormous dataset allows us to compare (i) a closed national market (A-shares) with an international market (B-shares), (ii) individuals and institutions and (iii) real investors to random strategies with respect to timing that share otherwise all other characteristics. We find that more trading results in smaller net return due to trading frictions. We unveiled quantitative power laws with non-trivial exponents, that quantify the deterioration of performance with frequency and with holding period of the strategies used by investors. Random strategies are found to perform much better than real ones, both for winners and losers. Surprising large arbitrage opportunities exist, especially when using zero-intelligence strategies. This is a diagnostic of possible inefficiencies of these financial markets.Comment: 13 pages including 5 figures and 1 tabl